System.Reflection.TargetInvocationException

Question

I just updated my phone to WP8.1 and I created an update for my app yesterday and removed and added a few functions and suddenly one page doesn't work and throws a System.Reflection.TargetInvocationException.

App.xaml.cs:

using System;
using System.Diagnostics;
using System.Resources;
using System.Windows;
using System.Windows.Markup;
using System.Windows.Navigation;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;
using Knowledge_Organizer.Resources;

namespace Knowledge_Organizer
{
public partial class App : Application
{
    /// <summary>
    /// Provides easy access to the root frame of the Phone Application.
    /// </summary>
    /// <returns>The root frame of the Phone Application.</returns>
    public static PhoneApplicationFrame RootFrame { get; private set; }

    /// <summary>
    /// Constructor for the Application object.
    /// </summary>
    public App()
    {
        // Global handler for uncaught exceptions.
        UnhandledException += Application_UnhandledException;

        // Standard XAML initialization
        InitializeComponent();

        // Phone-specific initialization
        InitializePhoneApplication();

        // Language display initialization
        InitializeLanguage();

        // Show graphics profiling information while debugging.
        if (Debugger.IsAttached)
        {
            // Display the current frame rate counters.
            Application.Current.Host.Settings.EnableFrameRateCounter = true;

            // Show the areas of the app that are being redrawn in each frame.
            //Application.Current.Host.Settings.EnableRedrawRegions = true;

            // Enable non-production analysis visualization mode,
            // which shows areas of a page that are handed off to GPU with a colored overlay.
            //Application.Current.Host.Settings.EnableCacheVisualization = true;

            // Prevent the screen from turning off while under the debugger by disabling
            // the application's idle detection.
            // Caution:- Use this under debug mode only. Application that disables user idle detection will continue to run
            // and consume battery power when the user is not using the phone.
            PhoneApplicationService.Current.UserIdleDetectionMode = IdleDetectionMode.Disabled;
        }

    }

    // Code to execute when the application is launching (eg, from Start)
    // This code will not execute when the application is reactivated
    private void Application_Launching(object sender, LaunchingEventArgs e)
    {
    }

    // Code to execute when the application is activated (brought to foreground)
    // This code will not execute when the application is first launched
    private void Application_Activated(object sender, ActivatedEventArgs e)
    {
    }

    // Code to execute when the application is deactivated (sent to background)
    // This code will not execute when the application is closing
    private void Application_Deactivated(object sender, DeactivatedEventArgs e)
    {
    }

    // Code to execute when the application is closing (eg, user hit Back)
    // This code will not execute when the application is deactivated
    private void Application_Closing(object sender, ClosingEventArgs e)
    {
    }

    // Code to execute if a navigation fails
    private void RootFrame_NavigationFailed(object sender, NavigationFailedEventArgs e)
    {
        if (Debugger.IsAttached)
        {
            // A navigation has failed; break into the debugger
            Debugger.Break();
        }
    }

    // Code to execute on Unhandled Exceptions
    private void Application_UnhandledException(object sender, ApplicationUnhandledExceptionEventArgs e)
    {
        if (Debugger.IsAttached)
        {
            // An unhandled exception has occurred; break into the debugger
            Debugger.Break();
        }
    }


    #region Phone application initialization

    // Avoid double-initialization
    private bool phoneApplicationInitialized = false;

    // Do not add any additional code to this method
    private void InitializePhoneApplication()
    {
        if (phoneApplicationInitialized)
            return;

        // Create the frame but don't set it as RootVisual yet; this allows the splash
        // screen to remain active until the application is ready to render.
        RootFrame = new PhoneApplicationFrame();
        RootFrame.Navigated += CompleteInitializePhoneApplication;

        // Handle navigation failures
        RootFrame.NavigationFailed += RootFrame_NavigationFailed;

        // Handle reset requests for clearing the backstack
        RootFrame.Navigated += CheckForResetNavigation;

        // Ensure we don't initialize again
        phoneApplicationInitialized = true;
    }

    // Do not add any additional code to this method
    private void CompleteInitializePhoneApplication(object sender, NavigationEventArgs e)
    {
        // Set the root visual to allow the application to render
        if (RootVisual != RootFrame)
            RootVisual = RootFrame;

        // Remove this handler since it is no longer needed
        RootFrame.Navigated -= CompleteInitializePhoneApplication;
    }

    private void CheckForResetNavigation(object sender, NavigationEventArgs e)
    {
        // If the app has received a 'reset' navigation, then we need to check
        // on the next navigation to see if the page stack should be reset
        if (e.NavigationMode == NavigationMode.Reset)
            RootFrame.Navigated += ClearBackStackAfterReset;
    }

    private void ClearBackStackAfterReset(object sender, NavigationEventArgs e)
    {
        // Unregister the event so it doesn't get called again
        RootFrame.Navigated -= ClearBackStackAfterReset;

        // Only clear the stack for 'new' (forward) and 'refresh' navigations
        if (e.NavigationMode != NavigationMode.New && e.NavigationMode != NavigationMode.Refresh)
            return;

        // For UI consistency, clear the entire page stack
        while (RootFrame.RemoveBackEntry() != null)
        {
            ; // do nothing
        }
    }

    #endregion

    // Initialize the app's font and flow direction as defined in its localized resource strings.
    //
    // To ensure that the font of your application is aligned with its supported languages and that the
    // FlowDirection for each of those languages follows its traditional direction, ResourceLanguage
    // and ResourceFlowDirection should be initialized in each resx file to match these values with that
    // file's culture. For example:
    //
    // AppResources.es-ES.resx
    //    ResourceLanguage's value should be "es-ES"
    //    ResourceFlowDirection's value should be "LeftToRight"
    //
    // AppResources.ar-SA.resx
    //     ResourceLanguage's value should be "ar-SA"
    //     ResourceFlowDirection's value should be "RightToLeft"
    //
    // For more info on localizing Windows Phone apps see http://go.microsoft.com/fwlink/?LinkId=262072.
    //
    private void InitializeLanguage()
    {
        try
        {
            // Set the font to match the display language defined by the
            // ResourceLanguage resource string for each supported language.
            //
            // Fall back to the font of the neutral language if the Display
            // language of the phone is not supported.
            //
            // If a compiler error is hit then ResourceLanguage is missing from
            // the resource file.
            RootFrame.Language = XmlLanguage.GetLanguage(AppResources.ResourceLanguage);

            // Set the FlowDirection of all elements under the root frame based
            // on the ResourceFlowDirection resource string for each
            // supported language.
            //
            // If a compiler error is hit then ResourceFlowDirection is missing from
            // the resource file.
            FlowDirection flow = (FlowDirection)Enum.Parse(typeof(FlowDirection), AppResources.ResourceFlowDirection);
            RootFrame.FlowDirection = flow;
        }
        catch
        {
            // If an exception is caught here it is most likely due to either
            // ResourceLangauge not being correctly set to a supported language
            // code or ResourceFlowDirection is set to a value other than LeftToRight
            // or RightToLeft.

            if (Debugger.IsAttached)
            {
                Debugger.Break();
            }

            throw;
        }
    }

    private void ApplicationBarIconButton_Click(object sender, EventArgs e)
    {

    }

    private void ApplicationBarIconButton_Click_1(object sender, EventArgs e)
    {

    }
}
}

Error: > Knowledge Organizer.ni.DLL!Knowledge_Organizer.App.RootFrame_NavigationFailed(object sender, System.Windows.Navigation.NavigationFailedEventArgs e) Line 92 C#

        // Code to execute if a navigation fails
    private void RootFrame_NavigationFailed(object sender, NavigationFailedEventArgs e)
    {
        if (Debugger.IsAttached)
        {
            // A navigation has failed; break into the debugger
            Debugger.Break();
        }
    }

Answer 1

EDIT.

Solution was extremely simple - the page.xaml.cs used 1 & 2 as reference when initialized the appbar instead of 0 & 1 - which caused it to not find the number 2 AppBarIconButton - that threw the exception. Solution:

                // Initialize these so that we can edit them
            deletenotesBtn = ApplicationBar.Buttons[0] as Microsoft.Phone.Shell.ApplicationBarIconButton;
            addnoteBtn = ApplicationBar.Buttons[1] as Microsoft.Phone.Shell.ApplicationBarIconButton;